Solar radiation receiver comprising a quartz window system for the closure of the receiver

ABSTRACT

A solar radiation receiver includes a quartz window system for the closure of the receiver having intermediate tubes/bars ( 1 M) and end tubes/bars ( 1 E) arranged in parallel forming a sheet contiguously to close an opening in a delimiting surface of the solar receiver and a seal ( 1 A) which has a cross section with the shape of an eight or convex lens, being the seal ( 1 A) located between every two tubes/bars ( 1 M,  1 E). The seal ( 1 A) having a first auxiliary generatrix ( 1 A 1 ) in a throat of the cross section. The intermediate tubes/bars ( 1 M) and the end tubes/bars ( 1 E) include respectively a first intermediate ( 1 M 1 ) and an end generatrix ( 1 E 1 ) in contact with the first auxiliary generatrix ( 1 A 1 ), forming a union wall of the seal ( 1 A) with an intermediate tube/bar ( 1 M) and an end tube/bar ( 1 E). The end tubes/bars ( 1 E) include a second external generatrix ( 1 E 2 ) contacting an edge of the opening forming a union wall of the end tube/bar ( 1 E) with the edge of the opening.

FIELD OF THE INVENTION

The present invention refers to a solar radiation receiver comprising a quartz window system for the closure and thermal insulation of the receiver hot cavity.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,421,102 discloses a number of quartz glass pipes disposed between a device for supplying a transparent gaseous medium and a device for exhausting the heated medium. Within each quartz glass pipe a number of glass strips, running parallel to one another, are accommodated. The adjacent glass strips are held by spacers at a distance which corresponds to the thickness of the glass strips. The glass strips are lightly tinted so that they absorb the incident radiation only partially. The coefficient of absorption of the glass strips amounts to about 0.1, so that about 90% of the incident solar radiation exits from the glass strips again and falls upon a further glass strip. In this way, the insolated energy is distributed over the entirety of the regions of the glass strips, so that all locations of the glass strips are heated evenly, and no location of the glass strips is overheated. The heat in the glass strips is transmitted to the gaseous medium flowing through inside the glass pipes and between the glass strips and is exhausted. This apparatus is particularly suitable for being disposed in a tower of a solar power plant in which the solar rays are directed at the top of the tower by means of a plurality of reflectors disposed on the ground.

DESCRIPTION OF THE INVENTION

An aspect of the invention refers to solar radiation receiver comprising a a quartz window system for the closure of the receiver such as the one defined in the set of claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a brief description of a series of drawings which will help understand the invention better relating clearly to an embodiment of said invention which is presented as a non-limiting example thereof.

FIG. 1 is a diagram of a crosss section of the invention.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

An embodiment of the invention refers to a solar radiation receiver comprising a quartz window system for the closure of the receiver characterized in that the quartz window system comprises:

1a) a plurality of intermediate tubes/bars (1M) and a plurality of end tubes/bars (1E) having a prismatic or cylindrical shape (the tubes offer more resistance with less weight) arranged:

-   -   1a1) in parallel, forming a sheet with an inner face and an         outer face;     -   1a2) contiguously, to form a resistant structure of the sheet         and to close an opening in a delimiting surface of the solar         receiver;

1b) sealing means (1A) which can be made of glass fiber, since it is a material more elastic than glass, having a cross section selected between a substantially eight shape and convex lens, the sealing means (1A) being located between every two tubes/bars (1M, 1E);

wherein:

1c) the sealing means (1A) comprise a first auxiliary generatrix (1A1) in a throat of the cross section;

1d) the intermediate tubes/bars (1M) comprise a first intermediate generatrix (1M1) in contact with the first auxiliary generatrix (1A1), to form a union wall of the sealing means (1A) with an intermediate tube/bar (1M);

1e) the end tubes/bars (1E) comprise a first external generatrix (1E1) in contact with the first auxiliary generatrix (1A1), to form a union wall of the sealing means (1A) with an end tube/bar (1E);

1f) the end tubes/bars (1 E) comprise a second external generatrix (1E2) arranged to contact in an gastight way an edge of the opening to form a union wall of an end tube/bar (1E) with the edge of the opening;

forming the assembly a closure or sealing system.

According to other characteristics of the invention:

The tubes/bars (1M, 1E) have a cross section selected between circular and polygonal.

The tubes (1M, 1E) have an open cross section, that is, with the shape of a sector instead of a closed geometrical figure, to reduce the number of surfaces to be crossed by solar radiation. The system is planned to work at operation temperatures between room temperature at the outer face and up to 1500K at the inner face.

The tubes/bars (1M, 1E) have a geometry and dimensions arranged to withstand the pressure difference between the inner face and the outer face.

The tubes/bars (1M, 1E) have a structure with a shape selected between arch and plane arranged to absorb dilatations without loosing gas sealing.

The solar radiation receiver also comprises a flat glass pane or panel (2) enveloping the inner face arranged to cover the opening where:

6a) the flat glass pane or panel (2) comprises an inner surface (21) oriented to the receiver cavity and an outer surface (2E) oriented to the inner face of the sheet;

6b) the intermediate tubes/bars (1M) comprise a second intermediate generatrix (1M2) in contact with the outer surface (2E), to form a union wall of the flat glass pane or panel (2) with an intermediate tube/bar (1M).

The flat glass pane or panel (2) rests on the intermediate tubes/bars (1M) to reduce possible mechanical strain in the flat glass pane or panel. It is held fast by the inner pressure in the receiver cavity.

The sealing means (1A) are arranged to be pushed against the tubes/bars (1E, 1M) by a pressure difference between the inner face and the outer face, the geometry of the sealing means (1A) adapting itself to favour contact between the sealing means (1A) and the tubes/bars (1E, 1M), and thus reducing possible gas leaks.

The system also comprises refrigeration means (1ER, 1MR) to refrigerate the tubes/bars (1E, 1M) through gas flow in the interior and/or exterior of the tubes/bars (1E, 1M).

The tubes/bars (1E, 1M) are covered, at least in part, by an antireflective layer (1RX) and/or dichroic filter (1D) at different wavelengths.

The tubes/bars (1E, 1M) are covered, at least in part, by a refractive layer (1RF) arranged to refract the solar rays in a desired direction, regardless of the behaviour of the quartz window. 

1. A solar radiation receiver comprising a quartz window system for the closure of the receiver, the quartz window system comprises: a plurality of intermediate tubes/bars and a plurality of end tubes/bars arranged: in parallel forming a sheet with an inner face and an outer face; contiguously to form a resistant structure of the sheet and to close an opening in a delimiting surface of the solar receiver; sealing means having a cross section selected between a substantially eight shape and convex lens, the sealing means being located between every two tubes/bars; wherein: the sealing means comprise a first auxiliary generatrix in a throat of the cross section; the intermediate tubes/bars comprise a first intermediate generatrix in contact with the first auxiliary generatrix, to form a union wall of the sealing means with an intermediate tube/bar; the end tubes/bars comprise a first end generatrix in contact with the first auxiliary generatrix, to form a union wall of the sealing means with an end tube/bar (1E); the end tubes/bars comprise a second end generatrix (1E2) arranged to contact an edge of the opening to form a union wall of the end tube/bar (1E) with the edge of the opening.
 2. The solar radiation receiver according to claim 1, wherein the tubes/bars have a cross section selected between circular and polygonal.
 3. The solar radiation receiver according to claim 1, wherein the tubes have an open cross section to reduce a number of surfaces to be crossed by solar radiation.
 4. The solar radiation receiver according to claim 1, wherein the tubes/bars have a geometry and dimensions arranged to withstand the pressure difference between the inner face and the outer face.
 5. The solar radiation receiver according to claim 1, wherein the tubes/bars have a structure with a shape selected between arch and plane arranged to absorb dilatations without losing gas sealing.
 6. The solar radiation receiver according to claim 1, further comprising a flat glass pane enveloping the inner face arranged to cover the opening wherein: the flat glass pane comprises an inner surface oriented to the receiver cavity and an outer surface oriented to the inner face of the sheet; the intermediate tubes/bars comprise a second intermediate generatrix in contact with the outer surface, to form a union wall of the flat glass pane with an intermediate tube/bar.
 7. The solar radiation receiver according to claim 1, wherein the sealing means are arranged to be pushed against the tubes/bars by a pressure difference between the inner face and the outer face, the geometry of the sealing means adapting to favor contact between the sealing means and the tubes/bars.
 8. The solar radiation receiver according to claim 1, further comprising refrigeration means to refrigerate the tubes/bars through gas flow in the interior and/or exterior of the tubes/bars.
 9. The solar radiation receiver according to claim 1, wherein the tubes/bars are covered, at least in part, by an antireflective layer or dichroic filter at different wavelengths.
 10. The solar radiation receiver according to claim 1, wherein the tubes/bars are covered, at least in part, by a refractive layer arranged to refract the solar rays in a desired direction, regardless of behavior of the quartz window. 